261128487240 has 96 divisors (see below), whose sum is σ = 851731690680. Its totient is φ = 69382849536.

The previous prime is 261128487239. The next prime is 261128487251. The reversal of 261128487240 is 42784821162.

261128487240 is a `hidden beast` number, since 2 + 6 + 1 + 128 + 487 + 2 + 40 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 210576360996 + 50552126244 = 458886^2 + 224838^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1209589 + ... + 1409028.

Almost surely, 2^261128487240 is an apocalyptic number.

261128487240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261128487240 is an abundant number, since it is smaller than the sum of its proper divisors (590603203440).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261128487240 is a wasteful number, since it uses less digits than its factorization.

261128487240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2618911 (or 2618904 counting only the distinct ones).

The product of its (nonzero) digits is 344064, while the sum is 45.

The spelling of 261128487240 in words is "two hundred sixty-one billion, one hundred twenty-eight million, four hundred eighty-seven thousand, two hundred forty".